Composite lawn edging

Abstract

The lawn edging (10) is formed by extruding a thermoplastic resin, preferably a thermoplastic resin such as polyethylene containing a dispersion of prevulcanized elastomer granules through a die (62) having a vertical die orifice (64) for forming the wall (12) of the channel (16). The vertical die orifice (64) also contains an element for forming protrusions (20) on a surface of the wall (12). The element preferably forms a horizontal edge on the protrusion (20). The feed rate of the element can be higher than the adjacent sections of the wall (12) such that the extruded material backs up in the die (62) and intermittently feeds through the outlet orifice (64). The channel (16) can contain a lower bead (34) and an upper hollow head member (14) which can be coated with a liquid impervious film (100) and perforated by a laser (120) to form spray apertures (122).

Description

This invention relates to a lawn barrier and more particularly this invention relates to an improved synthetic composite lawn edging which acts as a divider between lawn areas containing different types of plants or ground cover.1. Background of the InventionMany lawns are landscaped to contain discrete areas or beds of ground cover such as grass, plants or non-growing materials such as stone or bark. In order to prevent growth across the common border; it is quite common to install a physical barrier at the border such as strips of wood, metal, brick or cement walls, or lawn edging formed of synthetic resin.2. Description of the Prior ArtA popular form of synthetic resin lawn edging is in the form of a flange having an enlarged tube and a pair of anchoring means such as upwardly facing lips are provided between the lips and bottom of the flange as disclosed in U.S. Pat. No. 4,281,473.This lawn edging is formed from polyethylene. It is very rigid and inflexible. The edging is market...

AI Technical Summary

Benefits of technology

The mixture is extruded to form a lawn edging having a rough surface. The rough surface intensifies the frictional resistance of the buried edging reducing the tendency of the edging to creep out of the ground. The composite rubber-polymer lawn edging is much more flexible, pliable and bendable than an equivalent polyethylene edging. It can be bent into tighter radii to follow contours of garden beds without cracking or kinking. It can also be wound into tighter spirals to make smaller packages requiring less shelf space.

The lawn edging of the invention contributes to the environment by using a recycled product that otherwise would accumulate and degrade the environment. The lawn edging of the invention is more flexible than prior products, can be installed with less force, can be bent into tighter radii and has less tendency to come out of the ground after installation.

Problems solved by technology

They are a fire hazard when stored in sites above the ground.

It is difficult to separate the steel and fabric cord from the rubber.

Since the rubber is revulcanized to a cross-linked form, the rubber cannot be recovered by solution in solvent.

It is not economical to degrade the long chain rubber molecules to smaller hydrocarbons by thermal or catalytic methods.

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